Framework for assessment of magnetic equilibrium controller performance on the MAST upgrade spherical tokamak

Here, in this work we present the assessment framework for magnetic equilibrium controllers on MAST Upgrade spherical tokamak (MAST-U) spherical tokamak. Such controllers are essential for the MAST-U since exhaust physics and core-edge integration studies require advanced divertor plasma configurations. The developed framework is based on the TokSys suite of plasma control codes, which was adapted and upgraded for MAST-U. However, extra capabilities were added on top of TokSys to support the development of new control algorithms, deployment of controllers to the plasma control system (PCS) and evaluation of their performance. The controller assessment was realized via closed-loop integrated control simulations with the actual MAST-U PCS and different physics-based plasma models. Since all components of the assessment chain were experimentally validated, these simulations provide qualified controllers applicable for direct use in the experiment. This resulted in the successful experimental demonstration of advanced plasma shape control on MAST-U with minimal on-machine development time. A similar methodology would be beneficial to other tokamaks, both existing and future.. Authors: Lvovskiy, Andrey [General Atomics, San Diego, CA (United States)] (ORCID:0000000236491169); Anand, Himank [General Atomics, San Diego, CA (United States)] (ORCID:0000000296325680); Welander, Anders S. [General Atomics, San Diego, CA (United States)] (ORCID:0009000550637047); Kochan, Martin [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)] (ORCID:0009000796165828); Vincent, Charles [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)] (ORCID:000000027227409X). DOE Contract: AC05-00OR22725; AC52-07NA27344; SC0018991; SC0022272. Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; controller assessment; discharge simulation; plasma shape control